A hepatitis E outbreak by genotype 4 virus in Shandong province, China

Hepatitis E vaccine was available in China in 2012, but the priority population for immunization is not clear. In 2013, a hepatitis E outbreak occurred in a company of Shandong province, China where most employees moved from other provinces and dined at the company's cafeteria. A total of fourteen (19%, 14/73) case-patients were identified, and three of them had symptomatic infection with one death. The proportion of symptomatic infection was much higher among those aged ⩾50 years than those aged <50 years (2/2 vs. 1/12, P = 0.03), and higher in males than females (3/8 vs. 0/6, P = 0.21). Food in the company's cafeteria might be the possible source of the outbreak. The findings from this outbreak investigation indicate that individuals aged ⩾50 years, particularly males, might be the population of top priority for hepatitis E vaccination in China.